Thank you for that helpful glimpse into MTB geometry design. And thank you to @bturman as well. No doubt some of the detail will show up in discussions of mountain bike geometry taking place elsewhere on the web.

Its a trivially simple but nonetheless good idea like pretty much everything Pacenti comes up with. Allowing the patent though would be a travesty. As the stem with the horizontal top tube length determines the 'cockpit' of the bike and as the cockpit must be correctly matched to the rider to achieve a good fit radically reducing stem length in order to achieve some short stem ideal will not normally make a lot of sense - it just compromises the cockpit dimensions. Short stems are really for bikes that are deliberately designed to use them or for riders who are riding bikes that they are ill suited to that could benefit from a shortened cockpit.

Canfield clearly believes in short chainstays, the question is why this short? It is commonly held that short versus long will confer some advantages while blunting others - greater agility, less high speed stability, more difficulty in maintaining traction while climbing. Perhaps Canfield would dispute the received wisdom. And is that steep seat tube angle there for its own sake or because the seat tube simply had to make way for the large wheel during a suspension compression? It would be good to hear from Canfield on these issues.

I think you and @devin-m both have some degree of truth on your side. In the unavoidable trade off between anti-squat and pedal kickback Canfield (initially with the Balance bike) and Banshee have been working with design recipes that are not too dissimilar. I would add that Mondraker despite their different looking bikes also seems to be inspired by a similar design notion. I think you could be overemphasising Canfield's originality in that all three mentioned companies have produced noteworthy bikes. That said this bike looks like it could be the real deal and I eagerly await reviews of it.

Are you aware of any attempt to quantify losses for the Hammerschmidt? That would be interesting information to have. Also, there is the question of the overall rotated mass which you have emphasised - it is serious enough but on a Hammerschmidt style device perhaps less of a concern than for a full gearbox. Still, the overall picture isn't only about losses but also gains. If a rider can go quicker and safer in enough places because of the unique benefits of a certain suspension and drivetrain setup then that is the offset that justifies any new inefficiencies. Some inefficiencies are manageable rather than fatal. This kind of thing is best proved on the race track.

For the reasons already mentioned by @Primoz it is difficult to commit to a design like this for anything other than DH. That enduro bikes are being sold with 1x drivetrains does not mean that all designers or riders want to forgo the option to use 2x (or even 3x) drivetrains - multiple chainrings suit general trail riding better and are a good option for riders who never intend to take their enduro bike into competitive racing. But bikes designed with this kind of drivetrain - idlers and chain rerouting - are pretty much 1x only, and a lot of riders may balk at that. There is a solution though - the now almost forgotten internally geared crankset. If people really like this bike design they should call for greater effort from the manufacturers for something along the lines of the Hammerschmidt but revised and updated to be suitable for use in current enduro bike designs.

I certainly hope that happens. Unifying suspension bike design across all bikes in a future V5, as happened with the V3 range, would be great. But, even if something like that might happen down the line it is still years away. For now it looks like only this V4 bike will be truly outstanding.

Yes, a 100% Brake Squat (Anti-rise) is about as good as you can do to minimize unsettling chassis motion (rise at the rear that may also be accompanied by dive at the front) occasioned by braking but you should not assume that rear end traction is necessarily best served by a 'high' BS strategy. Different design strategies may be called for when optimizing rear braking for the sake of preserving bike geometry (i.e. a neutral or 100% BS strategy) as against optimizing rear braking for the sake of preserving traction. Transient forces at the contact patch under braking have a big impact on traction. As it happens braking configurations with relatively lower BS tend to have less sharp variations in these transient forces and gradual changes in load at the contact patch are less likely to cause loss of traction.

None of this implies that lower brake squat designs are free of problems. They are at a disadvantage compared to higher BS bikes from a geometry equilibrium point of view. Also, if a bike has brakes with poor modulation there is nothing that low BS can do about it. And there is a world of difference between having to slow the bike with the rear brakes on a relatively flat surface while heading into a sharp turn (low BS would in general be advantageous in this context) as against finding it necessary to use the rear brakes with the suspension already heavily compressed in a rock garden, say. BS of around 100% tends to interfere less with designed and intended suspension operation in a situation where it becomes necessary to brake while traversing rough ground.

Sadly, with braking, nothing is simple and not just the percentage of BS but also whether it is rising or falling also affects bike behaviour during deceleration. Some horst-links, split pivots and ABP bikes (Trek) have BS curves where the BS starts low and rises over the travel range. I suspect that is the best arrangement overall. The i-Track suspension designer seems to hold this view - see http://www.i-tracksuspension.com/suspensiontheory.html

While there are apparently a number of different drop-out options, the statement that, "the static chainstay length is 430 or 435-mm" does not sit well with the geometry chart that indicates the chainstay length is 425mm. And what is being referred to when the writer states, "it is still shorter on the SUPREME DH V4 (450mm rather than 457mm) to maintain a lively bike." Maybe these numbers actually mean something but the relevant explanations are missing.

A few of your critics have not grasped your point, apparently. That is not too gracious considering you acknowledge that the bike would, "eat steep, rocky stuff for breakfast." But that lengthening rear-centre that is the great advantage of high pivots in rocky stuff - it assists the quality of shock absorption and reduces the loss of bike momentum while ploughing through rough stuff - is also the bane of these bikes in high speed cornering especially riding berms. The suspension of all bikes packs down slowly in these situations and in this context a lengthening rear-centre is not optimal for the maintenance of momentum i.e. carrying speed. Quite the opposite, bikes with rearward axle paths will tend to slow down a bit more in this scenario than those with a more conventional design. That is not too serious but a lot of riders report a degree of sluggishness accelerating out of corners, which for racers at least, is quite important.

That said, Commencal seem to have done what they can with respect to LR escalation to provide support just at the points a design of this sort tends to exhibit its less endearing qualities, so that could go some way to mitigating any shortcomings.

Finally, there is no need to make guesses about the Anti-squat curve or wheel rate graphs etc. for this bike. linkagedesign.blogspot.com.es will normally have a full kinematic and dynamic analysis of a bike posted shortly after sound information on the bike appears. There is a translator included on the site that makes reading in English and other languages easy.

@boomslang Well, thank you for your informative comment. I'm sure that there is a lot there of general relevance for DH bike frame design and construction. You wouldn't be too shocked to learn that there are those of us who continue to consider the older frame design to be the better one overall. So, I welcome the news - widely reported and I hope reliable - that a 27.5in version of that bike will continue to be available in aluminium.